1. Field
The following description relates to a sensing system using a Hall sensor and to a Hall sensor arrangement procedure in a terminal including a display screen.
2. Description of Related Art
U.S. Pat. No. 6,701,166 relates to a switch that detects an open or closed state of a flip-type or folder-type radio terminal that has first and second structures joined to each other to have an open or closed state. The switch includes a Hall sensor that generates voltage according to the strength of an input magnetic field and inversely proportional to the distance to a magnet, a variable amplifier that variably amplifies the voltage from the hall sensor to output a variably amplified voltage signal in response to a control signal, and a comparator that compares the signal from the variable amplifier with a reference voltage to output a signal that indicates whether the terminal is in an open state or a closed state. The sensing value of the switch may be adjusted to sense the opening or closing of a folder of a terminal.
While the use of a Hall sensor to detect whether the flip cover opens or closes is discussed, a mechanism of preventing inaccurate detection when an angle of opening of a flip cover reaches about 360 degrees is not discussed in the patent.
In the event that the angle of opening of a flip cover is 0 degree, a magnet is close to the Hall sensor and the Hall sensor may detect a strong magnetic field. In response to the detection of the strong magnetic field, the Hall sensor may be used to determine that the flip cover is in a closed state.
However, in the event that the angle of opening of the flip cover reaches 360 degrees, a magnet is also located close to the Hall sensor. Thus, a strong magnetic field may be detected by the Hall sensor. A shielding sheet may be used to block the magnetic field from the Hall sensor.
The shielding sheet may be produced through a metallic material blocking a magnetic field flow. In response to the angle of opening of the flip cover being about 360 degrees, the shielding sheet may block the magnetic field generated from the magnet 210 so that the full strength of the magnetic field may not be detected by the Hall sensor. When the Hall sensor does not sense the strong magnetic field due to the blocking of the magnetic filed by the shielding sheet, the flip cover 200 may be continuously determined to be in an open state.
However, the procedure of determining the state of the flip cover using the shielding sheet additionally requires the use of a shielding sheet and may result in inaccurately determining an open state of the flip cover according to a position of the shielding sheet. Furthermore, a production of a display terminal requires an additional procedure of including the shielding sheet, which results in an increase in production cost.